The Indian cement industry is globally the second largest producer of cement and is largely dominated by about 30 main players. The extent of the production for cement is shown by around 200+ heavy scale cement producing plants and about 365 smaller ones. This is supported by the continuous market demand for the product even through changing times in the global and domestic market. India is considered to be the best cement producer in the world.
With all these positives comes one major disadvantage, the cement industry is the most significant and among the largest contributors too air pollution. Globally, around 7% of carbon emissions are generated by the cement industry. The emissions of Particulate Matter are drastically increasing and are considered to be amongst the most harmful kind of pollutant released into the air.
Sustainable pollution control practices that can be followed by the industry as a whole:
• Air pollution can be regularly be checked with the use of electrostatic precipitators
• Fly ash can be actively be used to substitute the use of clinkers. Fly ash is commonly available in the market and helps in reducing emissions and fuels that are consumed by clinkers for the same purpose.
• Using green energy sources and alternative fuel sources to complete the production process is much more suitable in the long term that brings down the pollution drastically.
• Effective and efficient disposal of solid wastes by the process of co-processing. This refers to the idea of burning solid wastes in the high temperature of kilns by using the waste materials as fuel.
• Following the government regulations relating to the cement industry such as the cap on emissions of particulate matter.
• Investing in technology and better factors of production that will help a company reach the regulations and not surpass the set limits.
Types of pollutants emitted by the cement industry:
Even though the cement companies have heavily invested in pollution control systems the levels of actual emissions by the cement industry is heavily increasing. This causes companies to pay large fines as the pollution levels are above government norms. The most common pollutants released by the cement industry are:
• Methane
• Carbon di oxides
• Carbon monoxide
• Hydrocarbons
• NOx and SOx
The cement industry is also responsible for a majority in emissions of unaccounted or fugitive pollutants that not only cause harm to human health but also to the growth of plants and survival of animals, especially in and around the factories. This problem of emitting fugitive emissions is faced in every step of cement production and poses a huge challenge in being controlled effectively. The existing and available technology cannot be used easily to control fugitive emissions and are very expensive and time consuming to employ considering their influencing factors.
Steps in cement production that add to air pollution:
- Mining: this refers to a process where the raw material for cement production is mined from limestone quarries with the help of various sub processes such as drilling, blasting crushing and transportation/ storing. All these processes lead to high emissions of carbon di oxide as well as particulate matter that can be deadly to living things.
- Preparing raw materials: the mined raw materials which can be dry, wet or even semi-solid are mixed and ground at a consistent pace that also leads to emissions of fugitive dusts and pollutants along with particulate matter.
- Kiln Processing: this refers to a step where combustion takes place in the kiln where raw materials are heated which results in the production of hard spherical nodules or clinkers. The clinkers are further cooled by air blowers and then transported to cement mills. Clinkers are formed by burning the raw mix at high temperatures which is technically known as the process of calcination. This step is a major contributor to the pollution by the cement industry as it emits various pollutants such as carbon di oxide, carbon monoxide, hydrocarbons and Sox.
All these pollutants are released from the mixture that is burned and treated constantly, apart from the pollution caused by the fuel used for burning the mixture. - Milling of cement: this refers to the final step in producing cement where the produced clinkers are ground into a fine powder. Various chemicals are added so as to set the cement properly. There are various emissions and particulate matter that are released at this step as well.
- Packaging of cement: This refers to the step where the produced cement is displaced and sent to the desired locations. The emissions of particulate matter at this step are extremely high due to loading, transporting and unloading of cement from the warehouses to construction sites.
On a general note, VOC’s are also constantly released into the air during other industrial processes and steps in the production process. Hence it can be clearly started that most of the fugitive pollution from the cement industry comprises of particulate matter.
Controlling fugitive emissions in the cement industry:
The only solution that can be employed even in the long run with effective results is using pollution control systems that are designed to control pollution across large surface areas. This equipment should cover the totality of area including controls for pollution from sources that cannot be accounted for. Compared to other conventional modes of air pollution control affordable modes that do not require heavy maintenance and energy can be used sustainably. Monitoring the air quality in real time is also important and should be included in the equipment. This can be achieved with strategically placed sensors across the area which is connected to the pollution control device.
Using such tools and equipment’s for air pollution control will ensure that the productivity of employees and areas in and around the factories are well maintained and do not face any critical long term damage. This will also prevent and accidents caused due to air pollution visibility and such damages can be mitigated with preventive measures instead of using corrective measures post damage.
